Modeling of Wellbore Heat Transfer in Geothermal Production Well

Abstract

Abstract Electricity supply in Nigeria has been insufficient to aid development. It has also been observed that fossil fuels that supply energy has not been friendly to the environment, as a result an alternative energy source is needed. Geothermal energy has come to fill this gap. This work modelled wellbore heat transfer in geothermal wells and investigated the best heat mining fluid that will conserve heat during heat transfer at the wellbore during heat production. This work employed the mechanisms that greenhouse gases use to absorb heat from the sun and retain it to warm the earth. Simulation of heat extraction capability of steam and CO2 were studied. It was observed at reservoir conditions (248 °F) that steam Mass heat capacity (2.433 KJ/kg °F) is higher than that of CO2 (1.088 KJ/kg °F). At 204. 8 °F mass heat capacity of CO2 is 1.1915KJ/kg OF and that of steam is 2.4058 KJ/kg °F. This implies that steam retains more heat than CO2. From the study at wellbore fluid temperature of 276.8 °F, and at a flow rate of 1300 lb/hr, the wellbore heat transfer from steam (0.158 mmbtu/day) is slightly higher than that of CO2 (0.105 mmbtu/day). CO2 conserves more heat than steam when used as a heat transfer fluid. The heat transfer capabilities of the mining fluids determine the production capability of the heat resources and the quantity of electricity generation. The study recommended CO2 deployment as heat mining fluid in the exploitation of heat in geothermal resources in Nigeria. This will reduce the greenhouse effect of CO2 in our environment while also encouraging rapid development and economic growth, more especially with the rising cost of energy from fossil. Availability of geothermal energy will increase the supply of electricity in Nigeria.